Cancer kills more children than any other disease, but the impact of a child's death on families is understudied. Bereaved families may be at risk for numerous psychosocial difficulties, which can persist for years. Others may experience new competencies and personal growth (e.g., maturity, compassion) after the initial grieving period;a variety of risk and resistance factors (e.g., age, coping skills, and social support) may affect outcomes, but little is known about what ameliorates difficulties and what promotes resilience. A primary problem has been a lack of well-designed research on the topic. Our long-term goal is to reduce the suffering and morbidity of families affected by cancer and the loss of a child through controlled, longitudinal research on the psychosocial outcomes of these families. The objective of this application is to differentiate subgroups of siblings and parents in need of assistance and to identify modifiable factors associated with adjustment, in our four-site study, we will recruit 180 families of children who died from cancer in the past 3- 12 months, and 180 non-bereaved comparison families. One sibling (aged 8-17 years) from each bereaved family will be randomly selected to participate and matched to a classmate of the same gender, race, and age as a comparison. Data will be collected from multiple sources in each child's classroom (i.e., peer, teacher, child) and home (i.e., mother, father, child) during the first year post-loss (T1) and during a follow-up home visit one year later (T2). This information will identify specific factors and subgroups of bereaved individuals to target in clinical trials to hasten recovery from grief and prevent long-term morbidity. Aim 1: compare the psychosocial adjustment (i.e., social, emotional, behavioral, family functioning) of bereaved and comparison families over time and examine mediating and moderating associations. Aim 2: Examine the course of grief symptoms and psychosocial adjustment as a function of characteristics of the illness/death, the child's developmental level, and grief work.